JP6743373B2 - Aqueous ink and ink jet recording method - Google Patents

Description

The present invention relates to an ink, an inkjet recording method, and a recorded matter.

Non-permeable recording media such as plastic films are used in applications of packaging materials such as foods, beverages and daily necessities, and inks used for the non-permeable recording media have been developed.

For packaging fruits and bread, so-called front-printing packaging materials, which are directly printed on the surface of a plastic film due to low packaging cost, are often used.
As the packaging material, scratch resistance is required because the printed layer may be in direct contact with the printed layer or the box of the adjacent packaging, and the friction may cause the printed layer to be scraped off, resulting in unclear printed contents. .. For flexible packaging, polypropylene (PP) is often used among plastic films.

Polypropylene is a base material that is inexpensive and has many excellent properties such as moldability, chemical resistance, and heat resistance, so it is a material that is expected to have stable demand growth in the future, but with a polar synthetic resin. However, since it is non-polar and crystalline, it is difficult for the water-based ink to adhere to the polypropylene film and image formation is difficult.

Therefore, by containing the polyester-based polyurethane aqueous resin produced through the step of reacting the pigment and the chain extender in the ink, the ink ejection property and storage stability are good, and the adhesion to the PP film is good. In addition, a water-based inkjet recording ink for laminating which is excellent in laminating suitability has been proposed (for example, refer to Patent Document 1).

An object of the present invention is to provide an ink having excellent adhesion to a polypropylene film and good intermittent ejection stability.

The ink of the present invention as a means for solving the above problems contains water, a coloring material, an organic solvent, a resin, and resin particles, the resin contains an acrylic resin, and the resin particles are a polyolefin-modified polyester. Contains urethane resin.

According to the present invention, an ink having excellent adhesion to a polypropylene film and good intermittent ejection stability can be provided.

FIG. 1 is a perspective explanatory view showing an example of a serial type image forming apparatus. FIG. 2 is a perspective explanatory view showing an example of the main tank of the apparatus of FIG.

The ink of the present invention contains water, a coloring material, an organic solvent, a resin, and resin particles, the resin contains an acrylic resin, and the resin particles contain a polyolefin-modified polyester urethane resin.
In the ink of the present invention, in the conventional water-based ink, water is the main component and the liquid component is easily volatilized, so that the dispersion stability of the pigment is easily impaired at the nozzle portion, and ejection failure is likely to occur during intermittent ejection. This is based on the finding that in the ink containing the conventional polyester-based polyurethane aqueous resin produced through the step of reacting the pigment and the chain extender, non-ejection occurs during intermittent ejection. ..

The inventors of the present invention, regarding each ink containing at least a polyolefin-modified polyester urethane resin as a resin particle, a coloring material, water, and an organic solvent, examined the adhesiveness to a polypropylene film and the ejection property during intermittent ejection. However, although the reason is not clear, it was found that good adhesiveness to the polypropylene film and good dischargeability during intermittent discharge can be realized only when an ink containing an acrylic resin is used. It was

<Ink>
Hereinafter, the organic solvent, water, coloring material, resin, additive and the like used in the ink will be described.

<Resin>
The resin includes an acrylic resin and, if necessary, other resin.

<< acrylic resin >>
The acrylic resin is obtained by copolymerizing at least one of an acrylic acid monomer and a methacrylic acid monomer, and if necessary, at least one of an acrylic acid ester-based monomer and a methacrylic acid ester-based monomer, and another monomer. And a structural unit derived from at least one of an acrylic acid monomer and a methacrylic acid monomer, and if necessary, a structural unit derived from at least one of an acrylic acid ester monomer and a methacrylic acid ester monomer, and from another monomer And a structural unit of.

Examples of the acrylic acid monomer and methacrylic acid monomer include acrylic acid, methacrylic acid, and lithium salts, sodium salts, potassium salts, ammonium salts thereof, and the like. Among these, sodium acrylate is preferable.

Examples of the acrylic acid ester-based monomer and the methacrylic acid ester-based monomer include methyl acrylate, methyl methacrylate, -n-butyl acrylate, -n-butyl methacrylate, 2-ethylhexyl acrylate, and methacrylic acid-2. -Ethylhexyl, -n-octyl acrylate, -n-octyl methacrylate, dodecyl acrylate, dodecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, acrylic Unsaturated fatty acid esters such as acid-2-aminoethyl and methacrylic acid-2-aminoethyl; unsaturated fatty acid amides such as acrylamide, methacrylamide, N-methylacrylamide, N-methylmethacrylamide; acrylonitrile, methacrylonitrile And unsaturated nitriles; and salts thereof.

Examples of the other monomer include unsaturated acids such as crotonic acid, itaconic acid, maleic acid, fumaric acid, mesaconic acid, citraconic acid, aconitic acid and glutaconic acid, and salts and ester compounds thereof; maleic anhydride. Unsaturated acid anhydrides such as acids, itaconic anhydride, citraconic anhydride, and vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene, and the like.

As the acrylic resin, those synthesized appropriately may be used, or commercially available products may be used.
Examples of the commercially available products include Aron T-50, Aron A-210, Aron A-6330 (above, manufactured by Toagosei Co., Ltd.), AQUALIC DL, AQUALIC HL, AQUALIC GL (above, Nippon Shokubai Co., Ltd.). Manufactured) and the like.

Examples of the method for synthesizing the acrylic resin include a method including a polymerization step of radically polymerizing each monomer in an aqueous medium.
The polymerization initiator used in the polymerization step may be any substance that decomposes under polymerization conditions to form free radicals, and can be appropriately selected depending on the polymerization conditions. For example, peroxides and azo compounds. Is mentioned.
Examples of the peroxide include inorganic peroxides such as sodium persulfate and hydrogen peroxide; organic peroxides such as hydroperoxide, dialkyl peroxide, diacyl peroxide, and peroxyester. Examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis(2,4-dimethylvaleronitrile) and 2,2′-azobis(2-methylbutyronitrile). And so on.
The amount of the polymerization initiator used is not particularly limited and may be appropriately selected depending on the type, polymerization conditions and the like, but is preferably 1 part by mass or more and 5 parts by mass or less with respect to 100 parts by mass of the monomer mixture.

In the polymerization process, a chain transfer agent may be used to control the molecular weight. Examples of the chain transfer agent include lower alcohols, thiols, hypophosphite, bisulfite and the like.
Examples of the lower alcohols include isopropyl alcohol and the like. Examples of the thiols include mercaptoethanol and the like. Examples of the hypophosphite include sodium hypophosphite and potassium hypophosphite. Examples of the bisulfite include sodium bisulfite and the like.
The amount of the chain transfer agent used is not particularly limited and may be appropriately selected depending on the type, polymerization conditions and the like, but is preferably 5 parts by mass or more and 120 parts by mass or less with respect to 100 parts by mass of the monomer mixture.

The polymerization temperature of the monomer mixture in the polymerization step is usually 70° C. or higher and 100° C. or lower. When the polymerization temperature is within the above range, the load on the reactor can be suppressed while reducing the residual monomer in a short polymerization time.
As the method of the polymerization step, for example, (i) a method of adding a monomer mixture and a polymerization initiator under stirring of an aqueous medium heated to the above temperature, (ii) a monomer heated to the above temperature A method of adding a polymerization initiator under stirring of the mixture and the aqueous medium, (iii) under stirring of the aqueous medium containing a part of the monomer (single or mixture) heated to the above temperature, the remaining monomers and initiation of the polymerization The method of adding the agent may be mentioned.

After the polymerization step, a neutralization step can be performed if necessary. The neutralization step is the radical polymerization group included in the resulting copolymer by (-COOH and _-SO 3 H) partially neutralized (25% to 99%) or complete neutralization (100%) It is a process.
Examples of the neutralizing agent used in the neutralization step include sodium hydroxide (aqueous solution), ammonia (aqueous solution), potassium hydroxide (aqueous solution), and the like.
The pH of the reaction system in the neutralization step is usually pH 2.0 or higher and pH 11.0 or lower, preferably pH 6.0 or higher and pH 9.0 or lower.
When the aqueous medium used in the polymerization step contains water and an organic solvent, a step of distilling off the organic solvent may be performed before the neutralization step.

The coloring material is preferably added to the ink in a state in which the coloring material is previously stably dispersed in the aqueous medium by the acrylic resin. Examples of the method include the following (1) to (3). There is a method.
(1) A method in which an acrylic resin, a coloring material, and an aqueous medium are mixed together (2) A method in which a coloring material is added and mixed under stirring of a solution in which an acrylic resin is dissolved in an aqueous medium (3) Aqueous A method in which an acrylic resin is added to and mixed with a liquid in which a coloring material is added to a medium, the mixing means is not particularly limited, and a known stirring device may be appropriately selected depending on the purpose. Examples thereof include homomixers, homodispers, and homogenizers.

The content of the resin is not particularly limited and may be appropriately selected depending on the intended purpose. From the viewpoints of fixability, ink storage stability, and ejection reliability, the content of the resin is 0.01. The content is preferably 30% by mass or more and 30% by mass or less, and more preferably 0.1% by mass or more and 20% by mass or less.

<<Other resins>>
Examples of the other resins include urethane resins, polyester resins, vinyl acetate resins, styrene resins, butadiene resins, styrene-butadiene resins, vinyl chloride resins, and the like.

<Resin particles>
The resin particles contain a polyolefin-modified polyester urethane resin, and further contain other resins as necessary.
The resin particles may include resin particles made of a polyolefin-modified polyester urethane resin, or may include other resin particles made of the other resin.

<< polyolefin modified polyester urethane resin >>
The polyolefin-modified polyester urethane resin means a polyester urethane resin having a polyolefin skeleton in at least one of the main chain and side chains. The polyester urethane resin means a urethane resin obtained by reacting polyester polyol and polyisocyanate.
Generally, as the urethane resin, there are polyether urethane and polycarbonate urethane, but in the present invention, the resin particles may contain the polyester urethane resin in order to obtain sufficient abrasion resistance in practical use. is necessary.

As the polyolefin-modified polyester urethane resin, those synthesized appropriately may be used, or commercially available products may be used.
The method for synthesizing the polyolefin-modified polyester urethane resin is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the method described in Japanese Patent Application Laid-Open No. 10-72562 is suitable.
That is, as the method, a polyurethane-modified polyester polyol, other polyester polyol, polyisocyanate, a compound having an acidic group and at least two active hydrogen-containing groups in the molecule, a polyurethane resin comprising a chain extender A method of neutralizing the acid group with ammonia and/or organic amine and dispersing it in an aqueous medium is preferable.
Hereinafter, each material will be described.

-Polyolefin modified polyester polyol-
The polyolefin-modified polyester polyol means a polyolefin having a hydroxyl group at at least one of both ends and side chains of the molecule.
The method for producing the polyolefin-modified polyester polyol is not particularly limited and may be appropriately selected depending on the purpose. For example, dehydration polycondensation or transesterification reaction between a compound imparting an olefin group and a dicarboxylic acid is performed. , A method of obtaining a polyester having a terminal hydroxyl group, and the like.

Examples of the compound imparting an olefin group include carbon numbers such as 1,2-hexanediol, 1,2-octanediol, 1,2-decanediol, 1,2-dodecanediol, and 1,2-octadecanediol. 5 to 42 1,2-alkanediol; 6 to 43 carbon atoms such as glycerin monohexyl ether, glycerin monooctyl ether, glycerin mono-2-ethylhexyl ether, glycerin monodecyl ether, glycerin monododecyl ether, glycerin monooctadecyl ether, etc. C7 such as glycerin hexanoic acid monoester, glycerin octanoic acid monoester, glycerin-2-ethylhexanoic acid monoester, glycerin decanoic acid monoester, glycerin dodecanoic acid monoester, glycerin octadecanoic acid monoester, etc. .About.44 glycerin fatty acid monoester and the like. These may be used alone or in combination of two or more.

Examples of the dicarboxylic acid include C4-C10 aliphatic dicarboxylic acids such as adipic acid, succinic acid, sebacic acid, azelaic acid, fumaric acid, and maleic acid, and ester-forming derivatives thereof; phthalic acid and terephthalic acid. Examples thereof include acids, aromatic dicarboxylic acids such as isophthalic acid, and ester-forming derivatives thereof. These may be used alone or in combination of two or more.

-Polyester polyol-
Examples of the polyester polyols include those obtained by esterification reaction of low molecular weight polyols and polycarboxylic acids, polyesters obtained by ring-opening polymerization reaction of cyclic ester compounds such as ε-caprolactone, and copolymers thereof. Examples include polymerized polyester.
Examples of the low molecular weight polyol include ethylene glycol and propylene glycol.
Examples of the polycarboxylic acid include succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, and their anhydrides or ester-forming derivatives.

-Polyisocyanate-
The polyisocyanate is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate (TDI) and 2 ,6-tolylene diisocyanate, 4,4'-diphenylene methane diisocyanate (MDI), 2,4-diphenylmethane diisocyanate, 4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-di Aromatic polyisocyanates such as isocyanatobiphenyl, 3,3′-dimethyl-4,4′-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate, m-isocyanatophenylsulfonyl isocyanate and p-isocyanatophenylsulfonyl isocyanate. Compounds: ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanate Aliphatic polyisocyanate compounds such as natomethylcaproate, bis(2-isocyanatoethyl)fumarate, bis(2-isocyanatoethyl)carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate; isophorone Diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanatoethyl)-4-diclohexene-1,2- Examples thereof include alicyclic polycyanate compounds such as dicarboxylate, 2,5-norbornane diisocyanate, and 2,6-norbornane diisocyanate.
Among these, aliphatic or alicyclic diisocyanates are preferable from the viewpoint of requiring a coating film having long-term weather resistance.

-A compound having an acidic group and at least two active hydrogen-containing groups in the molecule-
Examples of the compound having an acid group and at least two active hydrogen groups in the molecule include glycolic acid, tartaric acid, 4,6-dihydroxyisophthalic acid, α,α-dimethylolpropionic acid, α,α-dimethylol. Butyric acid, α,α-dimethylolnonanoic acid, and hydroxy acids such as carboxyl group-containing polycaprolactone diol obtained by addition polymerization of these with caprolactone monomer; hydroxy sulfonic acids such as 1,7-dihydroxynaphthalene sulfonic acid; 2 , 4-diaminobenzenesulfonic acid and other aminosulfonic acids.
Among these, α,α-dimethylolpropionic acid, α,α-dimethylolbutyric acid, which is a compound having two hydroxyl groups and one carboxyl group in the molecule, and addition polymerization of a caprolactone monomer thereto The resulting carboxyl group-containing polycaprolactone diol is preferred.

-Chain extender-
Examples of the chain extender include polyamines and other active hydrogen atom-containing compounds.
Examples of the polyamine include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, 1,4-cyclohexane. Diamines such as diamines; polyamines such as diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazines such as hydrazine, N,N'-dimethylhydrazine, 1,6-hexamethylenebishydrazine; succinic acid dihydrazide, adipic acid dihydrazide , Dihydrazides such as glutaric acid dihydrazide, sebacic acid dihydrazide, and isophthalic acid dihydrazide.

The method for producing the polyolefin-modified polyester-based urethane resin particles is not particularly limited, and a conventionally commonly used production method can be appropriately selected according to the purpose, and examples thereof include the following methods. ..
First, in the absence of a solvent or in the presence of an organic solvent, the polyester polyol, the polyolefin-modified polyester polyol, and the polyisocyanate are reacted at an equivalent ratio in which an isocyanate group becomes excessive to produce an isocyanate-terminated urethane prepolymer. ..
The ratio of the polyester polyol to the polyolefin-modified polyester polyol at this time is preferably 60/40 or more in the molecular weight ratio (polyester polyol/polyolefin-modified polyester polyol) of sites derived from each polyol in the isocyanate-terminated urethane prepolymer, and 80 /20 or more is more preferable, and 90/10 or more is particularly preferable.
Then, the anionic group in the isocyanate-terminated urethane prepolymer is neutralized with the neutralizing agent, if necessary, and then reacted with the chain extender, and finally, if necessary, an organic solvent in the system. Can be obtained by removing
Examples of the organic solvent include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; acetic acid esters such as ethyl acetate and butyl acetate; nitriles such as acetonitrile; dimethylformamide, N-methylpyrrolidone, N. Examples include amides such as ethylpyrrolidone. These may be used alone or in combination of two or more.

The polyolefin-modified polyester urethane resin may be contained in the resin particles or may be resin particles made of itself. Ink can be obtained by mixing the resin particles with a material such as a coloring material or an organic solvent in the state of a resin emulsion in which water is used as a dispersion medium.
The resin emulsion may contain a dispersant such as a surfactant if necessary, but from the viewpoint of easily obtaining an ink having better coating film performance, a so-called self-emulsion type emulsion is used. preferable.

The polyolefin-modified polyester urethane resin in the self-emulsifying emulsion has an acid value of 5 mgKOH/g or more and 100 mgKOH/g or less and preferably contains an anionic group from the viewpoint of water dispersibility, and is 5 mgKOH/g or more and 50 mgKOH/mg or less. However, it is more preferable for imparting excellent scratch resistance and chemical resistance.
Further, as the anionic group, for example, a carboxyl group, a sulfonic acid group and the like can be used to obtain good water dispersion stability. To introduce these anionic groups into the resin, these anionic groups can be used. A monomer having

The content of the polyolefin-modified polyester-based urethane resin with respect to the total amount of the ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, from the viewpoint of fixability and ink storage stability, the content is 1% by mass. The amount is preferably 20% by mass or more and more preferably 2% by mass or more and 20% by mass or less from the viewpoint that the smoothness of the ink layer is further improved, high glossiness can be obtained, and the fixing property to the recording medium is also improved. preferable.

<<Other resins>>
Examples of the other resin include urethane resin, polyester resin, acrylic resin, vinyl acetate resin, styrene resin, butadiene resin, styrene-butadiene resin, vinyl chloride resin, styrene-acrylic resin, and acrylic resin. Examples include silicone resins.

As the other resin particles made of the other resin, those synthesized appropriately may be used, or commercially available products may be used. Examples of the commercially available products include Microgel E-1002, E-5002 (styrene-acrylic resin particles, manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin particles, manufactured by DIC Corporation), Boncoat 5454 (styrene). -Acrylic resin fine particles, manufactured by DIC Corporation), SAE-1014 (styrene-acrylic resin fine particles, manufactured by Nippon Zeon Co., Ltd.), Cybinol SK-200 (acrylic resin fine particles, manufactured by Saiden Chemical Co., Ltd.), Primal AC- 22, AC-61 (acrylic resin fine particles, manufactured by Rohm and Haas Co.), Nanocryl SBCX-2821, 3689 (acrylic silicone resin fine particles, manufactured by Toyo Ink Mfg. Co., Ltd.), #3070 (methyl methacrylate polymer resin) Fine particles, manufactured by Mikuni Dye Co., Ltd.) and the like.

The volume average particle diameter of the resin particles is not particularly limited and may be appropriately selected depending on the purpose, but is preferably 10 nm or more and 1,000 nm or less from the viewpoint of obtaining good fixability and high image hardness. It is more preferably 200 nm or more and more preferably 10 nm or more and 100 nm or less.
The volume average particle size can be measured using, for example, a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell KK).

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include polyhydric alcohols, ethers such as polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines, and sulfur-containing compounds.
Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol , 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl- Polyhydric alcohols such as 1,3-pentanediol and petriol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether Polyhydric alcohol alkyl ethers such as ethers, polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone , Nitrogen-containing heterocyclic compounds such as 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N,N-dimethylformamide, 3-methoxy-N,N- Amides such as dimethylpropionamide and 3-butoxy-N,N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate and ethylene carbonate. Etc.
It is preferable to use an organic solvent having a boiling point of 250° C. or less because it not only functions as a wetting agent but also obtains good drying properties.

These may be used alone or in combination of two or more. Among these, at least one selected from the group consisting of 1,2-propanediol, 1,2-butanediol, and 2,3-butanediol, while promoting film formation of the resin, It is preferable in that it is possible to prevent the coagulation of the above, the adhesion to polypropylene in a short time drying, and the good dischargeability at the time of intermittent discharge are improved.
When the organic solvent is at least one selected from the group consisting of 1,2-propanediol, 1,2-butanediol, and 2,3-butanediol, after printing (after the ink flying step). In the case of the recording method having a heating step, the film formation of the resin contained in the ink is promoted, and the robustness of the recorded matter is further improved, which is preferable.

The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose, but from the viewpoint of the drying property of the ink and the ejection reliability, 10% by mass or more and 60% by mass or less is preferable, 20 mass% or more and 60 mass% or less are more preferable.

When the content is 10% by mass or more, it is difficult to dry the ink and sufficient ejection stability is easily obtained, which is preferable. When the content is 60% by mass or less, the viscosity can be suppressed to be low and discharge is easy, which is preferable.

<Water>
The content of water in the ink is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 10% by mass or more and 90% by mass or less and 20% by mass or less from the viewpoint of the drying property of the ink and the ejection reliability. % To 60% by mass is more preferable.

The water is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, and distilled water; and ultrapure water. .. These may be used alone or in combination of two or more.

<Color material>
The color material is not particularly limited, and pigments and dyes can be used.
An inorganic pigment or an organic pigment can be used as the pigment. These may be used alone or in combination of two or more. Also, a mixed crystal may be used.
Examples of pigments that can be used include black pigments, yellow pigments, magenta pigments, cyan pigments, white pigments, green pigments, orange pigments, luster color pigments such as gold and silver, and metallic pigments.
As an inorganic pigment, in addition to titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, carbon black produced by a known method such as a contact method, a furnace method, or a thermal method. Can be used.
Further, as the organic pigment, an azo pigment, a polycyclic pigment (for example, a phthalocyanine pigment, a perylene pigment, a perinone pigment, an anthraquinone pigment, a quinacridone pigment, a dioxazine pigment, an indigo pigment, a thioindigo pigment, an isoindolinone pigment, a quinofuraron pigment, etc.) , Dye chelates (for example, basic dye chelates, acid dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, etc. can be used. Among these pigments, those having a good affinity with the solvent are preferably used. In addition, hollow resin particles and hollow inorganic particles can also be used.
Specific examples of the pigment include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, or copper and iron (CI pigment black 11) for black. , Metal oxides such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).
Further, for color, C.I. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 24, 34, 35, 37, 42 (yellow iron oxide), 53, 55, 74, 81, 83, 95, 97, 98, 100, 101, 104. , 108, 109, 110, 117, 120, 138, 150, 153, 155, 180, 185, 213, C.I. I. Pigment Orange 5, 13, 16, 17, 36, 43, 51, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22, 23, 31, 38, 48:2, 48:2 (Permanent Red 2B(Ca)), 48:3, 48:4, 49:1, 52: 2, 53:1, 57:1 (Brilliant Carmine 6B), 60:1, 63:1, 63:2, 64:1, 81, 83, 88, 101 (Bengara), 104, 105, 106, 108 ( Cadmium red), 112, 114, 122 (quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 184, 185, 190, 193, 202, 207, 208, 209, 213, 219, 224, 254, 264, C.I. I. Pigment Violet 1 (Rhodamine Lake), 3, 5:1, 16, 19, 23, 38, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue), 15:1, 15:2, 15:3, 15:4 (phthalocyanine blue), 16, 17:1, 56, 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, and the like.
The dye is not particularly limited, and an acid dye, a direct dye, a reactive dye, and a basic dye can be used, and one kind may be used alone, or two or more kinds may be used in combination.
Examples of the dye include C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Red 52,80,82,249,254,289, C.I. I. Acid Blue 9,45,249, C.I. I. Acid Black 1, 2, 24, 94, C.I. I. Food Black 1, 2, C.I. I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. I. Direct Red 1,4,9,80,81,225,227, C.I. I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. I. Dilectd Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. I. Reactive Red 14, 32, 55, 79, 249, C.I. I. Reactive Black 3, 4, 35 can be mentioned.

Hollow resin particles can be used as the coloring material for the white ink. The hollow resin particles are not particularly limited, and known particles can be used.
Examples of commercially available hollow resin particles include, as styrene-acrylic resin, MH5055 (manufactured by Zeon Corporation), Lowpaque OP-62, Lowpaque OP-84J, Lowpaque OP-91, Lowpaque HP-1055, Lowpaque HP-. 91, Rhopaque ULTRA (above, manufactured by Rohm & Haas Co., Ltd.), SX-863(A), SX-864(B), SX-866(A), SX-866(B) as a cross-linked styrene-acrylic resin. ), SX-868 (above, manufactured by JSR Corporation), Lowpaque ULTRA E, Lowpaque ULTRA DUAL (above, manufactured by Rohm and Haas).
The colorant is not particularly limited and may be appropriately selected depending on the purpose, but a pigment is preferable.

The content of the coloring material in the ink is preferably 0.1% by mass or more and 15% by mass or less, more preferably 1% by mass or more and 10% by mass, from the viewpoint of improving the image density, good fixing property and ejection stability. It is the following.

To disperse the pigment in the ink, a method of introducing a hydrophilic functional group into the pigment to form a self-dispersing pigment, a method of coating the surface of the pigment with a resin to disperse, a method of dispersing using a dispersant, And so on.
Examples of a method for introducing a hydrophilic functional group into a pigment to give a self-dispersing pigment include, for example, a self-dispersing pigment that is dispersible in water by adding a functional group such as a sulfone group or a carboxyl group to a pigment (for example, carbon). Can be used.
As a method for coating the surface of the pigment with a resin to disperse the pigment, a method in which the pigment is contained in microcapsules and can be dispersed in water can be used. This can be rephrased as a resin-coated pigment. In this case, it is not necessary for all the pigments mixed in the ink to be coated with the resin, and as long as the effect of the present invention is not impaired, uncoated pigments and partially coated pigments are dispersed in the ink. May be.
Examples of the method of dispersing using a dispersant include a method of dispersing using a known low molecular type dispersant or polymer type dispersant represented by a surfactant.
As the dispersant, for example, an anionic surfactant, a cationic surfactant, an amphoteric surfactant, a nonionic surfactant or the like can be used depending on the pigment.
Takemoto Yushi Co., Ltd.'s RT-100 (nonionic surfactant) and naphthalenesulfonic acid Na formalin condensate can also be suitably used as the dispersant.
The dispersants may be used alone or in combination of two or more.

As one aspect of the ink of the present invention, it is preferable that the coloring material contains a styrene-acrylic resin coated pigment.
Here, the styrene-acrylic resin-coated pigment means a pigment in which the styrene-acrylic resin is entirely or partially coated with a styrene-acrylic resin. By coating the pigment with the styrene-acrylic resin, the pigment can be stably dispersed in water. In this case, it is not necessary that all of the pigments mixed in the ink be coated with the styrene-acrylic resin, and the pigments that are not coated or partially coated are included as long as the effects of the present invention are not impaired. The pigment may be dispersed in the ink. The styrene-acrylic resin is one mode of the acrylic resin.

-Styrene-Acrylic resin-
The styrene-acrylic resin is at least one of a styrene-based monomer and a styrene macromer, at least one of an acrylic acid monomer, a methacrylic acid monomer, an acrylic acid ester-based monomer and a methacrylic acid ester-based monomer, and optionally other monomers. And a structural unit derived from at least one of a styrene monomer and a styrene macromer, and at least one of an acrylic acid monomer, a methacrylic acid monomer, an acrylic acid ester monomer and a methacrylic acid ester monomer. It is a copolymer having a structural unit derived from the above and, if necessary, a structural unit derived from another monomer.

Examples of the styrene-based monomer include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, tert-butylstyrene and the like.

The styrene macromer is not particularly limited as long as it has a polymerizable functional group at one end, and can be appropriately selected according to the purpose. For example, a styrene homopolymer having a polymerizable functional group at one end. , And a copolymer of at least one of the styrene-based monomers having a polymerizable functional group at one end and the other monomer.
The number average molecular weight of the styrene macromer is preferably 500 or more and 50,000 or less, more preferably 1,000 or more and 10,000 or less.

Examples of the other monomer include acrylonitrile and the like.
The content of the styrene-based monomer in the copolymer of the styrene-based monomer having a polymerizable functional group at one end and the other monomer is such that the pigment is sufficiently coated on the styrene-acrylic resin. From the viewpoint of the above, 60 mass% or more is preferable, and 70 mass% or more is more preferable.

The polymerizable functional group is preferably an acryloyloxy group or a methacryloyloxy group.

Examples of commercially available styrene macromers include AS-6, AS-6S, AN-6, AN-6S, HS-6, HS-6S (all manufactured by Toagosei Co., Ltd.).

Examples of the acrylic acid monomer, the methacrylic acid monomer, the acrylic acid ester-based monomer, and the methacrylic acid ester-based monomer include acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, -n-butyl acrylate, and methacrylic acid. Acid-n-butyl, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, -n-octyl acrylate, -n-octyl methacrylate, dodecyl acrylate, dodecyl methacrylate, octadecyl acrylate, octadecyl methacrylate, Unsaturated fatty acid esters such as cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate, isobornyl methacrylate, 2-aminoethyl acrylate and 2-aminoethyl methacrylate; acrylamide, methacrylamide, N-methylacrylamide, N -Unsaturated fatty acid amides such as methylmethacrylamide; unsaturated nitriles such as acrylonitrile and methacrylonitrile; and salts thereof.

The weight average molecular weight of the styrene-acrylic resin is not particularly limited and may be appropriately selected depending on the intended purpose, but from the viewpoint of print density and ejection reliability, 3,000 or more and 100,000 or less are preferable, It is more preferably 5,000 or more and 50,000 or less. The weight average molecular weight can be measured by, for example, polystyrene conversion by gel permeation chromatography (GPC).

The pigment coated with the styrene-acrylic resin may be an inorganic pigment or an organic pigment. These may be used alone or in combination of two or more. Also, mixed crystals may be used.

<Pigment dispersion>
It is possible to obtain ink by mixing a color material with a material such as water or an organic solvent. Further, it is also possible to manufacture an ink by mixing a pigment and other materials such as water and a dispersant to form a pigment dispersion, and mixing materials such as water and an organic solvent.
The pigment dispersion is obtained by dispersing water, a pigment, a pigment dispersant, and other components as necessary, and adjusting the particle size. A dispersion machine may be used for dispersion.
There is no particular limitation on the particle size of the pigment in the pigment dispersion, but since the dispersion stability of the pigment is good and the image quality such as ejection stability and image density is also high, the maximum frequency is 20 nm or more when converted to the maximum number. It is preferably 500 nm or less, more preferably 20 nm or more and 150 nm or less. The particle size of the pigment can be measured using a particle size analyzer (Nanotrack Wave-UT151, manufactured by Microtrack Bell KK).
The content of the pigment in the pigment dispersion is not particularly limited and may be appropriately selected depending on the purpose, but from the viewpoint of obtaining good ejection stability and increasing the image density, it is 0.1 mass. % Or more and 50% by mass or less is preferable, and 0.1% by mass or more and 30% by mass or less is more preferable.
The pigment dispersion is preferably degassed by filtering coarse particles with a filter, a centrifugal separator or the like, if necessary.

The particle size of the solid content in the ink is not particularly limited and can be appropriately selected according to the purpose. However, from the viewpoint of improving the image quality such as ejection stability and image density, the maximum number of times converted to the maximum number Is preferably 20 nm or more and 1000 nm or less, more preferably 20 nm or more and 150 nm or less. The solid content includes resin particles and pigment particles. The particle size can be measured using a particle size analyzer (Nanotrack Wave-UT 151, manufactured by Microtrack Bell KK).

<Additive>
If necessary, a surface active agent, a defoaming agent, an antiseptic/antifungal agent, an anticorrosive agent, a pH adjusting agent, etc. may be added to the ink.

<Surfactant>
As the surfactant, any of silicone-based surfactants, fluorine-based surfactants, amphoteric surfactants, nonionic surfactants, and anionic surfactants can be used.
The silicone surfactant is not particularly limited and can be appropriately selected according to the purpose. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, and side-chain both-end modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferable because they exhibit good properties as an aqueous surfactant. Further, as the silicone-based surfactant, a polyether-modified silicone-based surfactant can also be used, and examples thereof include a compound having a polyalkylene oxide structure introduced into the side chain of the Si moiety of dimethylsiloxane.
Examples of the fluorinated surfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphoric acid ester compound, a perfluoroalkyl ethylene oxide adduct and a perfluoroalkyl ether group in the side chain. A polyoxyalkylene ether polymer compound is particularly preferable because it has a low foaming property. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid and perfluoroalkyl sulfonate. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylic acid salts. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in its side chain include a sulfuric acid ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in its side chain and a perfluoroalkyl ether group in its side chain. Examples thereof include salts of polyoxyalkylene ether polymers. As counter ions of salts in these fluorine-based surfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH(CH ₂ CH ₂ OH) are used. ₃ etc. are mentioned.
Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.
Examples of nonionic surfactants include polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene alkylamines, polyoxyethylene alkylamides, polyoxyethylene propylene block polymers, sorbitan fatty acid esters, polyoxyethylene sorbitan. Examples thereof include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, lauryl salt, and salt of polyoxyethylene alkyl ether sulfate.
These may be used alone or in combination of two or more.

The content of the surfactant in the ink is appropriately selected depending on the intended purpose without any limitation, but it is 0.001% by mass from the viewpoint of excellent wettability and ejection stability and improving image quality. % Or more and 5 mass% or less is preferable, and 0.05 mass% or more and 5 mass% or less is more preferable.

<Antifoam>
The defoaming agent is not particularly limited, and examples thereof include a silicone defoaming agent, a polyether defoaming agent, and a fatty acid ester defoaming agent. These may be used alone or in combination of two or more. Among these, a silicone-based defoaming agent is preferable because of its excellent foam breaking effect.

<Antiseptic and fungicide>
The antiseptic/antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Rust preventive>
The rust preventive agent is not particularly limited, and examples thereof include acid sulfite and sodium thiosulfate.

<pH adjuster>
The pH adjuster is not particularly limited as long as it can adjust the pH to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

The physical properties of the ink are not particularly limited and may be appropriately selected depending on the purpose. For example, the viscosity, surface tension, pH and the like are preferably in the following ranges.
The viscosity of the ink at 25° C. is preferably 5 mPa·s or more and 30 mPa·s or less, from the viewpoint that the printing density and character quality are improved and good ejection properties are obtained, and 5 mPa·s or more and 25 mPa·s or less are preferable. More preferable. Here, as the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. The measurement conditions are 25° C., standard cone rotor (1°34′×R24), sample liquid volume 1.2 mL, rotation speed 50 rpm, and 3 minutes.
The surface tension of the ink is preferably 35 mN/m or less, and more preferably 32 mN/m or less at 25° C. from the viewpoint that the ink is preferably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12, and more preferably 8 to 11 from the viewpoint of preventing the corrosion of the metal member with which the ink comes into contact.

<Ink manufacturing method>
The method for producing the ink of the present invention is not particularly limited and may be appropriately selected depending on the intended purpose. For example, the water, the coloring material, the organic solvent, the resin, and the resin particles in an aqueous medium. Examples of the method include a method in which it is dispersed or dissolved in, and if necessary, mixed by stirring to prepare. Examples of the stirring and mixing include a stirrer using a normal stirring blade, a magnetic stirrer, and a high speed disperser.

<Pretreatment liquid>
The pretreatment liquid contains a coagulant, an organic solvent, and water, and may contain a surfactant, an antifoaming agent, a pH adjusting agent, an antiseptic/antifungal agent, an antirust agent, etc., if necessary.
As the organic solvent, the surfactant, the defoaming agent, the pH adjusting agent, the antiseptic/antifungal agent and the rust preventive agent, the same materials as those used in the ink can be used, and other materials used in the known treatment liquid can be used. ..
The type of aggregating agent is not particularly limited, and examples thereof include water-soluble cationic polymers, acids, polyvalent metal salts and the like.

<Post-treatment liquid>
The post-treatment liquid is not particularly limited as long as it can form a transparent layer. The post-treatment liquid is obtained by selecting and mixing an organic solvent, water, a resin, a surfactant, an antifoaming agent, a pH adjusting agent, an antiseptic/antifungal agent, an anticorrosive agent, etc., if necessary. Further, the post-treatment liquid may be applied to the entire recording area formed on the recording medium, or may be applied only to the area where the ink image is formed.

<Recording medium>
The recording medium is not particularly limited, and plain paper, glossy paper, special paper, cloth, and the like can be used, but good image formation can be performed using a non-permeable substrate.
The non-permeable base material is a base material having a surface with low water permeability and low absorbability, and includes a material that does not open to the outside even if there are many cavities inside, and more quantitatively. , Bristow method refers to a substrate having a water absorption amount of 10 mL/m ² or less from the start of contact to 30 msec ^1/2 .
As the non-permeable substrate, for example, a plastic film such as a vinyl chloride resin film, a polyethylene terephthalate (PET) film, polypropylene, polyethylene, a polycarbonate film can be preferably used.

As a commercial item of the said polypropylene film, P-2002, P-2161, P-4166 (above, Toyobo Co., Ltd. make), PA-20, PA-30, PA-20W (above, SUNTOX make), Examples include FOA, FOS, FOR (above, manufactured by Futamura Chemical Co., Ltd.).
Examples of commercially available products of the polyethylene terephthalate film include E-5100, E-5102 (above, Toyobo Co., Ltd.), P60, P375 (above, Toray Co., Ltd.), G2, G2P2, K, SL (above, Teijin DuPont Film Co., Ltd.) and the like.
Examples of commercial products of the nylon film include Harden films N-1100, N-1102, N-1200 (above, Toyobo Co., Ltd.), ON, NX, MS, NK (above, Unitika Co., Ltd.) and the like. Can be mentioned.

<Recorded matter>
The ink recorded matter of the present invention has an image formed by using the ink of the present invention on a recording medium.
A recorded matter can be obtained by recording with an inkjet recording apparatus and an inkjet recording method.

<Recording device, recording method>
The ink of the present invention can be suitably used for various recording apparatuses using an inkjet recording method, such as a printer, a facsimile apparatus, a copying apparatus, a printer/fax/copier compound machine, and a three-dimensional modeling apparatus.
In the present application, the recording device and the recording method are a device capable of ejecting ink, various treatment liquids, and the like onto a recording medium, and a method of recording using the device. The recording medium means a medium to which ink or various treatment liquids can be attached even temporarily.
This recording device can include not only a head portion for ejecting ink, but also means for feeding, conveying, and discharging a recording medium, and other devices such as a pre-processing device and a post-processing device. ..
The recording device and the recording method may have a heating means used in the heating step and a drying means used in the drying step. The heating means and the drying means include, for example, means for heating and drying the printing surface or the back surface of the recording medium. The heating means and the drying means are not particularly limited, but, for example, a warm air heater or an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording device and the recording method are not limited to those in which a significant image such as a character or a figure is visualized by ink. For example, it also includes one that forms a pattern such as a geometric pattern and one that models a three-dimensional image.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head unless otherwise limited.
Further, this recording device is not limited to a desktop type, and can be used as a wide recording device capable of printing on an A0 size recording medium or, for example, a continuous paper wound in a roll as a recording medium. It also includes a continuous form printer.
An example of the recording device will be described with reference to FIGS. FIG. 1 is a perspective explanatory view of the device. FIG. 2 is a perspective view of the main tank. The image forming apparatus 400 as an example of the recording apparatus is a serial type image forming apparatus. A mechanical section 420 is provided inside the exterior 401 of the image forming apparatus 400. Each ink storage portion 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), and yellow (Y) is packed with, for example, an aluminum laminate film. It is formed of a member. The ink container 411 is housed in a container case 414 made of plastics, for example. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided on the inner side of the opening when the cover 401c of the apparatus body is opened. The main tank 410 is detachably attached to the cartridge holder 404. As a result, the ink discharge ports 413 of the main tank 410 communicate with the ejection heads 434 for each color via the supply tubes 436 for each color, and ink can be ejected from the ejection head 434 to the recording medium.

This recording device can include not only a portion for ejecting ink, but also a device called a pre-processing device, a post-processing device, or the like.
As one mode of the pretreatment device and the posttreatment device, as in the case of inks such as black (K), cyan (C), magenta (M), and yellow (Y), a pretreatment liquid and a posttreatment liquid are included. There is a mode in which a liquid storage section and a liquid ejection head are added and a pretreatment liquid and a posttreatment liquid are ejected by an inkjet recording method.
As another aspect of the pretreatment apparatus and the posttreatment apparatus, there is an aspect in which a pretreatment apparatus and a posttreatment apparatus other than the ink jet recording method are provided, for example, by a blade coating method, a roll coating method, a spray coating method.

The method of using the ink is not limited to the ink jet recording method and can be widely used. In addition to the inkjet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

The ink of the present invention can be recorded with high image quality on a non-permeable substrate as the recording medium, but in order to form an image with higher image quality and higher abrasion resistance and adhesion, and under high-speed printing conditions. It is preferable to heat the recording medium during printing (for example, the ink flying step) from the viewpoint that the above can be dealt with. Further, it is preferable to include a heating step of heating the recording medium after printing (for example, an ink flying step).

The heating device used for heating the recording medium is not particularly limited, and a known heating device can be used according to the purpose, for example, forced air heating, radiant heating, conduction heating, high frequency drying, and micro. Examples include a device for wave drying. These may be used alone or in combination of two or more. The heating device may be incorporated in an existing inkjet printer or may be externally attached to the existing inkjet printer.

The heating temperature of the recording medium is appropriately selected depending on the intended purpose without any limitation, but the heating temperature during printing is preferably 30°C or higher and 60°C or lower. The heating temperature after printing is preferably controlled at 110°C or lower. The heating temperature is preferably high in consideration of the drying property, but when the heating temperature is equal to or lower than the upper limit value, the recording medium is not damaged and ejection failure due to warming of the ink head can be prevented. It is possible to form a uniform ink recording film.

Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to the following examples. In the examples, "part" is "part by mass", and "%" is "% by mass" excluding those in the evaluation criteria.

<Preparation of styrene-acrylic resin-coated pigment dispersion>
A dropping funnel and a Dimroth condenser were attached to the reaction vessel, and 20 parts of methyl ethyl ketone, 15 parts of isobornyl methacrylate, and styrene macromer (trade name: AS-6S, manufactured by Toagosei Co., Ltd.) in the reaction vessel were placed under a nitrogen atmosphere. Part, 5 parts of methacrylic acid, 7 parts of methyl methacrylate, and 0.9 parts of mercaptosuccinic acid are heated to 65° C. with stirring, and 35 parts of isobornyl methacrylate in a dropping funnel, styrene macromer (trade name) : AS-6S, manufactured by Toagosei Co., Ltd.) 7 parts, methacrylic acid 13 parts, methyl methacrylate 15 parts, mercaptosuccinic acid 2.1 parts, methyl ethyl ketone 80 parts, and 2,2′-azobis(2,4-dimethylvalero). A mixed solution of 2 parts of nitrile) was gradually added dropwise over 3 hours. After maintaining at 65° C. for 2 hours from the end of dropping, a solution of 0.3 parts of 2,2′-azobis(2,4-dimethylvaleronitrile) in 6 parts of methyl ethyl ketone was added, and further at 65° C. for 2 hours. The mixture was aged at 70° C. for 2 hours, a part of the obtained polymer solution was dried under reduced pressure at 105° C. for 2 hours, the solvent was removed, and a crude polymer dried product was obtained.
Neutralizer (20% sodium hydroxide aqueous solution) was added to 30 parts of 50% styrene-acrylic resin solution prepared by drying methyl ethyl ketone to neutralize salt-forming groups, and Pigment Red 122 (trade name: Fastogen Super Magenta RG , Manufactured by DIC Co., Ltd.) and kneaded with a roll mill. After dispersing the kneaded product in 100 parts of ion-exchanged water, the organic solvent was completely removed under reduced pressure at 60° C., and water was further removed to concentrate the mixture to obtain a styrene-acrylic resin-coated pigment having a solid content of 20%. A dispersion was obtained.

<Synthesis of acrylic resin 1>
150 parts of water was charged into a four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, and the temperature was raised to 80°C.
Then, while stirring, a mixture of 50 parts of ion-exchanged water, 80 parts of acrylic acid, 10 parts of methacrylic acid, 20 parts of ethylhexyl methacrylate, and 1 part of hydroxypropyl acrylate, and 10 parts of a 30% sodium persulfate aqueous solution were added to each of 3 parts. The mixture was dropped over a period of time to carry out a polymerization reaction at 80°C.
After completion of the dropping, the system was further aged for 1 hour while maintaining the system at 80° C. to complete the polymerization reaction.
Then, the reaction solution was completely neutralized with 120 parts of a 32% sodium hydroxide aqueous solution to obtain an acrylic resin 1 having a solid content concentration of 40%.

<Synthesis of acrylic resin 2>
In the synthesis of acrylic resin 1, butyl acrylate was used instead of ethylhexyl methacrylate, and N-methylol acrylamide was used instead of hydroxypropyl (meth)acrylate. Acrylic resin 2 having a concentration of 40% was obtained.

<Preparation of Black Pigment Dispersion 1>
Acrylic resin 12 parts and ion-exchanged water 78 parts were stirred with a TK homomixer (manufactured by PRIMIX Corporation) to obtain a uniform dispersant aqueous solution. 20 parts of carbon black pigment (Monarch 800, manufactured by Cabot Corporation) was added to this aqueous solution, and the mixture was stirred at a rotation speed of 4,000 rpm for 15 minutes and dispersed to obtain a black pigment dispersion 1.

<Preparation of Black Pigment Dispersion 2>
In the preparation of the black pigment dispersion 1, a black pigment was prepared in the same manner as the preparation of the black pigment dispersion 1, except that sodium polyacrylate (Aron T-50, manufactured by Toagosei Co., Ltd.) was used in place of the acrylic resin 1. Dispersion 2 was obtained.

<Preparation of Black Pigment Dispersion 3>
In the preparation of the black pigment dispersion 1, the black pigment dispersion was prepared in the same manner as the preparation of the black pigment dispersion 1 except that sodium polyacrylate (Aquaric DL, manufactured by Nippon Shokubai Co., Ltd.) was used in place of the acrylic resin 1. I got body 3.

<Preparation of cyan pigment dispersion>
In the preparation of the black pigment dispersion 1, a cyan pigment dispersion was prepared in the same manner as in the preparation of the black pigment dispersion 1, except that Pigment Blue 15:4 (SMART Cyan 3154BA, manufactured by SENSIENT) was used instead of carbon black. Obtained.

<Preparation of magenta pigment dispersion>
Pigment Red 122 (Pigment Red 122, manufactured by Sun Chemical Co.) was used in place of carbon black in the preparation of Black Pigment Dispersion 1, and Acrylic Resin 2 was used in place of Acrylic Resin 1 except that Acrylic Resin 2 was used. A magenta pigment dispersion was obtained in the same manner as in the preparation of 1.

<Preparation of yellow pigment dispersion>
Black Pigment Dispersion 1 except that Pigment Yellow 74 (SMART Yellow 3074BA, manufactured by SENSIENT) was used in place of carbon black in the preparation of Black Pigment Dispersion 1, and acrylic resin 2 was used in place of acrylic resin 1. A yellow pigment dispersion was obtained in the same manner as in (1).

<Preparation of Black Pigment Dispersion 4>
After premixing the following formulation mixture, it is an activator-dispersed pigment dispersion that is circulated and dispersed in a disk type bead mill (KDL type, Shinmaru Enterprises Co., Ltd., media: 0.3 mm diameter zirconia ball is used) for 7 hours. Black pigment dispersion 4 was obtained.
Carbon black pigment (Monarch 800, manufactured by Cabot) 20 parts Anionic surfactant (Pionin A-51-B, manufactured by Takemoto Yushi Co., Ltd.) 4 parts Ion-exchanged water 76 parts

<Preparation of Self-Dispersion Magenta Pigment Dispersion>
Pigment Red 122 (Pigment Red 122, manufactured by Sun Chemical Co., Ltd.), 100 g, was added to 3,000 mL of a 2.5 N (normal) sodium hypochlorite solution, and the mixture was stirred at a temperature of 60° C. and a speed of 300 rpm for 10 hours to be reacted. Oxidation treatment was performed to obtain a pigment having a carboxylic acid group on the surface of Pigment Red 122.
The reaction solution was filtered, the filtered Pigment Red 122 was neutralized with a sodium hydroxide solution, and subjected to ultrafiltration.
Then, ultrafiltration with a dialysis membrane was performed using the pigment dispersion and ion-exchanged water, and further ultrasonic dispersion was performed to obtain a self-dispersion magenta pigment dispersion in which the pigment solid content was concentrated to 20%. ..

The composition of each color material dispersion prepared is shown in Table 1 below.

<Preparation of polyolefin-modified polyester urethane resin emulsion A>
618 parts of polyester diol and 19 parts of 1,4-butanediol synthesized by a method similar to the method described in Synthesis Example 1 of JP-A-10-72562 in a pressure polymerization vessel equipped with a thermometer and a stirrer. , 102 parts of dimethylolpropionic acid, 290 parts of isophorone diisocyanate (IPDI), and 670 parts of acetone were charged and reacted at 80° C. for 10 hours under stirring to obtain an acetone solution of NCO-terminated polyurethane resin having an NCO content of 0.20%. .. The acetone solution was cooled to 30° C. and 42 parts of 28% ammonia water was added. Next, 1,515 parts of ion-exchanged water was added to the acetone solution, and acetone was removed at 50° C. to 60° C. under reduced pressure to obtain a polyurethane resin dispersion liquid having a solid content of 40.0% and a viscosity of 660 cP/25° C. The number average molecular weight (the same applies hereinafter) measured by gel permeation chromatography (GPC) of this resin was 15,000.
The obtained resin emulsion was subjected to dispersion treatment with a paint conditioner (manufactured by Red Devil Co., speed adjustable in the range of 50 rpm to 1,425 rpm), and measured by a particle size analyzer (Microtrack MODEL UPA9340, manufactured by Nikkiso Co., Ltd.). A polyolefin-modified polyester urethane resin emulsion A having a volume average particle diameter of 32 nm was obtained.

<Preparation of polyolefin-modified polyester urethane resin emulsion B>
In a separable flask equipped with a stirrer, two dropping funnels with pressure equalizing tubes, a thermometer, and a water-cooled condenser, the content of ethylene component was 48 mol%, Mn was 3,600, and Mw/Mn was 1.65. Then, 166.91 g of the ethylene-propylene copolymer, which was No. 1, was charged and the atmosphere was replaced with nitrogen.
Then, after raising the temperature to 160° C., at the same temperature, 490.60 g of light acrylate HOB-A (2-hydroxybutyl acrylate, manufactured by Kyoeisha Chemical Co., Ltd.), which had been weighed in a dropping funnel, and 10.71 g of excess. Di-tert-butyl oxide (Katayama Chemical Co., Ltd.) was added dropwise over 2 hours.
After the dropping, the reaction was performed at 160° C. for 2 hours, then the temperature was raised to 170° C., and the pressure-reduced treatment was performed for 3 hours under the conditions of 170° C. and 1.33 kPa or less to obtain a polyolefin-modified polyol.
Next, in a reaction vessel in which a stirrer, a reflux condenser and a thermometer were inserted, 1,500 g of polyester polyol (Polylite OD-X-2420, manufactured by DIC Corporation), 200 g of the polyolefin modified polyol, and 2,2-dimethylol. 220 g of propionic acid (DMPA) and 1,347 g of N-methylpyrrolidone (NMP) were charged under a nitrogen stream and heated to 60° C. to dissolve DMPA. Then, 4,4′-dicyclohexylmethane diisocyanate (1445 g) and dibutyltin dilaurate (catalyst) (2.6 g) were added, and the mixture was heated to 90° C. and subjected to urethanization reaction for 5 hours to obtain an isocyanate-terminated urethane prepolymer. .. The reaction mixture was cooled to 80° C., and 340 g of triethylamine was added to and mixed with it, 4,340 g of which was taken out and added to a mixed solution of 5,400 g of ion-exchanged water and 15 g of triethylamine with vigorous stirring. It was Then, 1,500 g of ice was added, 626 g of 35% 2-methyl-1,5-pentanediamine aqueous solution was added to carry out a chain extension reaction, and the solvent was distilled off so that the solid content concentration became 30%. Dispersion treatment was carried out in the same manner as in the case of the polyolefin-modified polyester urethane resin emulsion A to obtain a polyolefin-modified polyester urethane resin emulsion B having a volume average particle diameter of the resin particles of 121 nm.

<Preparation of Polyolefin Modified Polyether Urethane Resin Emulsion C>
In the preparation of the polyolefin-modified polyester urethane resin emulsion B, a polyolefin is used except that a polyether polyol (Hiflex D2000, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) is used instead of the polyester polyol (Polylite OD-X-2420). In the same manner as in the preparation of the modified polyester urethane resin emulsion B, a polyolefin-modified polyether-based urethane resin emulsion C having a volume average particle diameter of resin particles of 58 nm and a solid content concentration of 30% was obtained.

<Preparation of Polyester Urethane Resin Emulsion D>
In the prepolymer formation reaction of the polyolefin-modified polyester urethane resin emulsion B, the volume average particle diameter of the resin particles is 44 nm in the same manner as in the preparation of the polyolefin-modified polyester urethane resin emulsion B except that the polyolefin-modified polyol is not used at all. A polyester-based urethane resin emulsion D having a solid content concentration of 30% was obtained.

<Preparation of polyolefin resin emulsion E>
A propylene-based random copolymer (propylene:ethylene=96:4, mass ratio) produced by using a metallocene catalyst as a polymerization catalyst is supplied to a twin-screw extruder having a barrel temperature of 35° C. for thermal degradation, and a degraded propylene-based polymer. A random copolymer was obtained.
100 parts of a degraded propylene random copolymer, 4 parts of methyl methacrylate, 4 parts of ethylhexyl acrylate, and 3 parts of dicumyl peroxide were thoroughly mixed in advance and then fed to a twin-screw extruder for a residence time of 5 minutes. , Rotation speed 300 rpm, barrel temperature 120°C (first and second barrels), 180°C (third and fourth barrels), 100°C (fifth barrel), and 130°C (sixth to eighth barrels). The reaction was carried out to obtain an acrylic ester-polyolefin copolymer.
In a 2 L four-necked flask equipped with a stirrer, a cooling tube, a thermometer and a dropping funnel, 200 g of the obtained acrylic acid ester-polyolefin copolymer, 35 g of a surfactant (polyoxyethylene alkylamine), stearyl. 8 g of glycidyl ether and 36 g of toluene were added, and the mixture was kneaded at 120° C. for 30 minutes.
Thereafter, 8 g of 2-amino-2-methyl-1-propanol was added over 5 minutes, and after the addition was maintained for 5 minutes, 970 g of ion-exchanged water heated to 90° C. was added over 40 minutes.
After the toluene was distilled off by a reduced pressure treatment, the mixture was gradually cooled to room temperature with stirring, and the water content was adjusted so that the solid content concentration was 40%. A polyolefin resin emulsion E having a volume average particle diameter of the resin particles of 140 nm was obtained.

<Preparation of acrylic resin emulsion F>
A reaction vessel equipped with a stirrer, a reflux condenser, a dropping device, and a thermometer was charged with 900 g of ion-exchanged water and 1 g of sodium lauryl sulfate, and the temperature was raised to 70° C. under nitrogen with stirring.
Keeping the internal temperature at 70° C., adding 4 g of potassium persulfate as a polymerization initiator and dissolving it, 450 g of ion-exchanged water, 3 g of sodium lauryl sulfate, 20 g of acrylamide, 365 g of styrene, 545 g of butyl acrylate, and 10 g of methacrylic acid were stirred in advance. In addition to the emulsification, the emulsion prepared was continuously added dropwise to the reaction solution over 4 hours.
After completion of dropping, aging was carried out for 3 hours.
After cooling the obtained aqueous emulsion to room temperature, ion-exchanged water and an aqueous sodium hydroxide solution were added to adjust the solid content concentration to 30% and pH to 8, and the volume average of the resin particles was performed in the same manner as in the case of the resin emulsion A. An acrylic resin emulsion F having a particle size of 123 nm was obtained.

(Example 1)
Styrene-acrylic resin-coated pigment dispersion 20 parts, olefin-modified polyester urethane resin emulsion A 15 parts, 1,2-propanediol 30 parts, silicone surfactant (BY16-201, manufactured by Toray Dow Corning Co., Ltd.) 5 parts, antiseptic/antifungal agent (Proxel LV, manufactured by Abyssia) 0.1 part, and ion-exchanged water 33.4 parts were mixed and stirred, and an average pore diameter of 0.8 μm membrane filter (cell roll acetate type, manufactured by ADVANTEC) The ink of Example 1 was prepared by filtering with.

(Examples 2 to 21, and Comparative Examples 1 to 15)
Inks of Examples 2 to 21 and Comparative Examples 1 to 15 were prepared in the same manner as in Example 1 except that the prescriptions shown in Tables 2-1 to 2-7 below were changed. ..

(Comparative Example 16)
<Preparation of cyan pigment dispersion α>
20 parts of cyan pigment (FANTOGEN BLUE FSJ-SD, manufactured by DIC Co., Ltd.), 30 parts of pigment dispersant (Disperbyk-190, manufactured by Big Chemie Japan Co., Ltd.), 5 parts of isopropyl alcohol, and 45 parts of ion-exchanged water were stirred and mixed. After kneading and dispersing using a bead mill, coarse particles were removed by centrifugation and ion-exchanged water was added to obtain a cyan pigment dispersion α having a pigment concentration of 15%.

<Preparation of ink>
Cyan pigment dispersion α 20 parts, polyester-based polyurethane resin synthesized by hydrazine chain extension (Akrit WBR-601, manufactured by Taisei Fine Chemical Co., Ltd.) 8.8 parts, propylene glycol 10 parts, 1,3-butylene glycol 10 parts, interface 0.5 parts of an activator (Surfynol 440, manufactured by Air Products) and 56.1 parts of ion-exchanged water were mixed to prepare a mixed solution, which was then filtered with a filter having an average pore diameter of 0.5 μm (manufactured by ADVANTEC). An ink of Comparative Example 16 was obtained.

The "adhesiveness" and "intermittent ejection stability" of the inks of Examples 1 to 21 and Comparative Examples 1 to 16 thus produced were evaluated as follows. The results are shown in Table 3 below.

<Adhesion evaluation>
An ink jet printer (IPSiO GXe5500, manufactured by Ricoh Co., Ltd.) was filled with the inks prepared in Examples 1 to 21 and Comparative Examples 1 to 16, and ink was applied to a polypropylene (PP) film (Pyrene P2102, manufactured by Toyobo Co., Ltd.). A solid image of 5 cm×5 cm was printed so that the adhered amount was 9 g/m ² , and dried under conditions of 80° C. for 3 minutes and 80° C. for 90 seconds.

A cross-cut peeling test using a cloth adhesive tape (Nichiban Co., Ltd., 123LW-50) was performed on the solid portion of the printed image, and evaluated according to the following evaluation criteria. The allowable range is up to B.
[Evaluation criteria]
A: No peeling was observed in any of the 100 squares.
B: One or more and 5 or less of 100 squares were peeled off.
C: There are 6 or more peeled pieces out of 100 squares.

<Evaluation of intermittent ejection stability>
The inks prepared in Examples 1 to 21 and Comparative Examples 1 to 16 were filled in an inkjet printer (IPSiO GXe5500, manufactured by Ricoh Co., Ltd.), and head cleaning was performed under a temperature of 25° C. and a humidity of 15% RH. After cleaning the head, leave it uncapped and leave it at a temperature of 25°C and a humidity of 15%RH for 60 minutes and 90 minutes, then print a nozzle check pattern and visually check for ejection failure and jet turbulence. The evaluation criteria were as follows. The allowable range is up to B.
[Evaluation criteria]
A: There are no nozzles in which ejection failure and jet turbulence are observed.
B: There are nozzles in which a slight jet turbulence is recognized, but there are no non-ejection nozzles.
C: There is a nozzle in which ejection failure is recognized.

(Example 22)
The ink produced in Example 1 was filled in an inkjet printer (IPSiO GXe5500, manufactured by Ricoh Co., Ltd.), and the amount of ink adhered to the polypropylene (PP) film (Pyrene P2102, manufactured by Toyobo Co., Ltd.) was 9 g/m ² . Thus, a solid image of 5 cm×5 cm was printed and left at room temperature. On the next day, the solid pattern of the printed image was subjected to a cross-cut peeling test in the same manner as in Example 1 and evaluated according to the above evaluation criteria, and the evaluation was “B”.

The inks of Examples 1-21 are particularly preferred examples of the present invention. The inks of Examples 1 to 21 all have PP adhesion of "B" or more after being dried at 80° C. for 3 minutes and at 80° C. for 90 seconds, and as a result of being left for 60 minutes for intermittent ejection stability and left for 90 minutes, The evaluation is “B” or more, and excellent intermittent ejection stability can be realized while ensuring sufficient adhesion to polypropylene.

On the other hand, the inks of Comparative Examples 1 to 16 were evaluated as "C" by either the adhesiveness evaluation or the intermittent ejection stability evaluation, and both the sufficient adhesion to polypropylene and the excellent intermittent ejection stability were realized. Not done.

As described above, with the configuration of the present invention, it is possible to provide good adhesion to the polypropylene film and good dischargeability during intermittent discharge.

Aspects of the present invention are as follows, for example.
<1> Contains water, a coloring material, an organic solvent, a resin, and resin particles,
The resin contains an acrylic resin,
The ink is characterized in that the resin particles contain a polyolefin-modified polyester urethane resin.
<2> The ink according to <1>, wherein the color material is a pigment.
<3> The ink according to any one of <1> to <2>, wherein the coloring material contains a styrene-acrylic resin-coated pigment in which a styrene-acrylic resin is partially or entirely coated with a styrene-acrylic resin. ..
<4> The ink according to <3>, wherein the styrene-acrylic resin has a weight average molecular weight of 5,000 or more and 50,000 or less.
<5> The organic solvent contains at least one selected from the group consisting of 1,2-propanediol, 1,2-butanediol, and 2,3-butanediol. <1> to <4> The ink according to any one of 1.
<6> The ink according to any one of <1> to <5>, wherein the content of the organic solvent is 20% by mass or more and 60% by mass or less.
<7> The ink according to any one of <1> to <6>, wherein the content of the polyolefin-modified polyester urethane resin is 2% by mass or more and 20% by mass or less.
<8> The ink according to any one of <1> to <7>, wherein the polyolefin-modified polyester urethane resin has an acid value of 5 mgKOH/g or more and 50 mgKOH/mg or less.
<9> The ink according to any one of <1> to <8>, wherein the volume average particle diameter of the resin particles is 10 nm or more and 200 nm or less.
<10> The ink according to any one of <1> to <9>, wherein the content of the acrylic resin is 0.05 parts by mass or more and 1 part by mass or less based on 100 parts by mass of the pigment.
<11> The ink according to any one of <1> to <10>, further including a surfactant.
<12> An inkjet recording method comprising a step of applying a stimulus to the ink according to any one of <1> to <11> and applying the stimulus to a recording medium.
<13> The inkjet recording method according to <12>, which includes a heating step of heating the recording medium after the ink flying step.
<14> The inkjet recording method according to any one of <12> to <13>, wherein the recording medium is a polypropylene film.
<15> An ink jet recording apparatus, comprising: the ink according to any one of <1> to <11>; and an ink flying unit that applies a stimulus to the ink and applies the ink to a recording medium.
<16> The inkjet recording apparatus according to <15>, further including a heating unit that heats the recording medium.
<17> The inkjet recording device according to any one of <15> to <16>, wherein the recording medium is a polypropylene film.
<18> A recorded matter comprising a recording medium and a recording layer containing a coloring material, an acrylic resin, and a polyolefin-modified polyester urethane resin on the recording medium.
<19> The recorded matter according to <18>, wherein the recording layer further contains a styrene-acrylic resin.
<20> The recording medium according to any one of <18> to <19>, wherein the recording medium is a polypropylene film.

The ink according to any one of <1> to <11>, the inkjet recording method according to any of <12> to <14>, and the inkjet recording according to any of <15> to <17>. The apparatus and the recorded matter according to any one of <18> to <20> can solve the above-mentioned problems in the related art and achieve the object of the present invention.

JP, 2013-1755, A

400 image forming apparatus

Claims (5)

Contains water, colorant, organic solvent, resin, and resin particles,
The resin contains an acrylic resin,
The resin particles contain a polyolefin-modified polyester urethane resin ,
The water- based ink, wherein the water content is 10% by mass or more and 90% by mass or less . The water-based ink according to claim 1, wherein the coloring material contains a styrene-acrylic resin-coated pigment in which the surface of the pigment is wholly or partially coated with a styrene-acrylic resin. 3. The organic solvent according to claim 1, wherein the organic solvent contains at least one selected from the group consisting of 1,2-propanediol, 1,2-butanediol, and 2,3-butanediol. Water-based ink. An ink jet recording method comprising a step of applying a stimulus to the water-based ink according to claim 1 and applying the stimulus to a recording medium. The inkjet recording method according to claim 4, further comprising a heating step of heating the recording medium after the ink flying step.